feat(knowledge-base): 添加知识库文件全库检索功能

- 新增相对路径字段替代原有的metadata存储方式
- 实现跨知识库文件检索接口searchFiles
- 添加前端全库检索页面和相关API调用
- 优化文件路径处理和数据库索引配置
- 统一请求参数类型定义为RequestPayload和RequestParams
- 简化RagFile模型中的元数据结构设计

frontend/src/pages/KnowledgeBase/Detail/KnowledgeBaseDetail.tsx

@@ -17,7 +17,7 @@ import {
   EditOutlined,
   ReloadOutlined,
 } from "@ant-design/icons";
-import { useNavigate, useParams } from "react-router";
+import { useNavigate, useParams, useSearchParams } from "react-router";
 import DetailHeader from "@/components/DetailHeader";
 import { SearchControls } from "@/components/SearchControls";
 import { KBFile, KnowledgeBaseItem } from "../knowledge-base.model";
@@ -58,7 +58,6 @@ type KBFileRow = KBFile & {
 };
 
 const PATH_SEPARATOR = "/";
-const RELATIVE_PATH_KEY = "relativePath";
 const normalizePath = (value?: string) =>
   (value ?? "").replace(/\\/g, PATH_SEPARATOR);
 
@@ -81,17 +80,13 @@ const splitRelativePath = (fullPath: string, prefix: string) => {
 };
 
 const resolveFileRelativePath = (file: KBFile) => {
-  const metadata = file?.metadata as Record<string, unknown> | undefined;
-  const metadataPath =
-    metadata && typeof metadata[RELATIVE_PATH_KEY] === "string"
-      ? String(metadata[RELATIVE_PATH_KEY])
-      : "";
-  const rawPath = metadataPath || file.fileName || file.name || "";
+  const rawPath = file.relativePath || file.fileName || file.name || "";
   return normalizePath(rawPath).replace(/^\/+/, "");
 };
 
 const KnowledgeBaseDetailPage: React.FC = () => {
   const navigate = useNavigate();
+  const [searchParams] = useSearchParams();
   const { message } = App.useApp();
   const { id } = useParams<{ id: string }>();
   const [knowledgeBase, setKnowledgeBase] = useState<KnowledgeBaseItem | undefined>(undefined);
@@ -158,6 +153,16 @@ const KnowledgeBaseDetailPage: React.FC = () => {
     }
   }, [id, fetchKnowledgeBaseDetails]);
 
+  useEffect(() => {
+    if (!id) {
+      return;
+    }
+    const prefixParam = searchParams.get("prefix");
+    const fileNameParam = searchParams.get("fileName");
+    setFilePrefix(prefixParam ? normalizePrefix(prefixParam) : "");
+    setFileKeyword(fileNameParam ? fileNameParam : "");
+  }, [id, searchParams]);
+
   useEffect(() => {
     if (id) {
       fetchFiles();